Conventional single ended quartz (SEQ) lamps for use in projection applications typically consist of a quartz wire lamp focused and cemented in a ceramic base with two attached base pins leading externally of the lamp envelope for connection to a source of power. The quartz wire lamp includes a filament, foil leads that are disposed within the seal region of the lamp envelope, and external molybdenum leads which are connected to power. The ceramic base includes brass pins with center holes inserted into openings in the ceramic base, and typically staked in place. The electrical connection from a power source to the filament is a four piece system comprising the brass pins, nickel wire leads, molybdenum wire leads, and molybdenum foil leads.
Specifically, one embodiment of an SEQ lamp known in the art and sold by General Electric is shown in FIGS. 1-3. This SEQ lamp is a standard quartz wire lamp with a filament housed inside a quartz envelope. The two ends of the filament are welded to wire lamp foil leads. The foil leads are then sealed in one end of the quartz envelope. External molybdenum leads welded to the wire lamp foil leads extend out of the seal.
Specifically, two 0.060" (1.5 mm) diameter, nickel plated brass pins are inserted and staked into holes in the ceramic base where the holes extend from the inside cavity of the base to the other end of the ceramic base. The nickel plated brass pins are hollow. Further, each pin has a center hole therethrough and out the outer end.
The external molybdenum leads on the wire lamp are then trimmed below the seal with no more remaining length than needed to weld outer extension leads thereon. Nickel outer leads are welded to the exposed portions of the external molybdenum leads. The welded outer extension leads are threaded through the center holes in base pins to the correct light center length (LCL), i.e. the distance from the center of the filament to the bottom of the ceramic base.
The wire lamp and ceramic base are clamped in place and the excess welded outer extension lead wire is trimmed away. The remaining lead wire is welded to the inside of the nickel plated brass pins. Cement is introduced through a center hole in the bottom of the base whereby the inside cavity of the ceramic base around the wire lamp seal is filled with cement. The wire lamp is then adjusted to center the coil over the base in both the up-down (vertical) and the left-right (horizontal) direction. Finally, the lamp assembly is heated to set the cement.
This and other current designs for based SEQ lamps for projection applications include numerous parts that assist in the focusing operation during assembly. The focusing operation adds significant time and labor expense to the manufacture of each SEQ lamp for projection applications. These current designs with large ceramic bases with large aliquots of cement around quartz wire lamp seals retain heat and thus may prohibit cooling needed for prevention of lamp failure from overheated seals.